Build a React application called "Overseen", an AI-powered copilot for people managers. The app connects to a manager's calendar, "joins" 1:1 meetings to transcribe them, analyzes behavioral patterns (like talking ratios and feedback gaps), and auto-drafts performance reviews.

I need a fully functional frontend demo with rich, realistic mock data. Do NOT use a generic SaaS aesthetic or standard shadcn/ui defaults. Instead, use a "neo-brutalist" / editorial tech design system.

Design System & Styling Rules:

• Framework: React with Tailwind CSS.
• Typography:
  • Headings: 'Space Grotesk' (bold, tight tracking)
  • Body: 'Inter'
  • Labels/Data/Badges: 'JetBrains Mono' (uppercase, tracking-wider, text-sm or text-xs)
• Colors:
  • Background Primary: #FDFBF7 (Cream)
  • Background Secondary: #F2EFE9
  • Text Primary: #1A1A1A (Charcoal)
  • Text Secondary: #4A4A4A
  • Accents: Orange (#E05D3A), Green (#7A9E7E), Blue (#4A6FA5), Purple (#8B6B9E)
• UI Elements (Neo-Brutalist):
  • Use thick borders: border-2 border-[#1A1A1A]
  • Use hard offset shadows instead of soft drop shadows: box-shadow: 4px 4px 0px #1A1A1A
  • Hover states should translate the element slightly and increase the shadow to 6px 6px 0px.
  • No rounded corners (use rounded-none).

Required Libraries:

• lucide-react for icons.
• recharts for data visualization.
• react-router-dom for routing.
• date-fns for date formatting.

Application Structure & Pages:

1. Landing Page (/):
   • Sticky navbar with logo and "Try Demo" button.
   • Hero section with a bold headline: "Become the manager they never want to leave."
   • 3 Feature cards (Pre-Meeting Briefs, Behavioral Insights, Auto-Drafted Reviews) using the brutalist card style and different accent colors.
2. App Layout (/app):
   • Sidebar navigation (Dashboard, Team, Meetings, Reviews) with active states.
   • Mobile-responsive (hamburger menu on small screens).
3. Dashboard (/app):
   • Top stats row: Team Sentiment (%), Action Items, Avg Talk Ratio, Upcoming 1:1s.
   • "Team Overview" table listing team members, their status (Trending Up, Needs Attention, Stable), and next meeting date.
   • "AI Insights" panel flagging specific issues (e.g., "Warning: You haven't given James positive feedback in 42 days" or "Pattern: You spoke 80% of the time in your last 4 meetings with Sarah").
4. Team Member Detail (/app/team/:id):
   • Profile header with avatar, role, and sentiment score.
   • A horizontal stacked Bar Chart (using Recharts) showing the "Talking Ratio" between the Manager and the Report.
   • A list of past meeting summaries with this specific team member, showing open action items.
5. Meeting Detail (/app/meeting/:id):
   • Header with meeting date, time, and participant.
   • AI Summary block.
   • Two-column layout:
     • Left: Action Items checklist and AI Meeting Insights (e.g., "Sentiment was positive when discussing design work").
     • Right: A full chat-style transcript of the meeting with timestamps.
6. Performance Review (/app/review/:id):
   • A document-style view of an AI-drafted performance review.
   • Sections: Executive Summary, Core Strengths (numbered list), Areas for Growth, and Proposed Goals for Next Period.
   • Action buttons to "Edit Draft" or "Export to HRIS".

Mock Data Requirements: